EDIT:I too encountered the the SDK-Error, starting PyCharm without a batch file, right from the windows start menue. When it asked for opening/creating a project, i choosed "Create New Project" and then under "Project Interpreter" choosed Existing Interpreter with just pointing to a OSGEO4W-python.exe never used before in pycharm, it shows the SDK-Error. I bet you can delete the bad project and create a new one, starting pycharm with the correct batch file...